Application of water-soluble polyvinyl alcohol-based film patches on laser microporated skin facilitates intradermal macromolecule and nanoparticle delivery

Advancing immunotherapy using biomaterials to control tissue, cellular, and molecular level immune signaling in skin

Immunotherapies have been transformative in many areas, including cancer treatments, allergies, and autoimmune diseases. However, significant challenges persist in extending the reach of these technologies to new indications and patients. Some of the major hurdles include narrow applicability to patient groups, transient efficacy, high cost burdens, poor immunogenicity, and side effects or off-target toxicity that results from lack of disease-specificity and inefficient delivery. Thus, there is a significant need for strategies that control immune responses generated by immunotherapies while targeting infection, cancer, allergy, and autoimmunity. Being the outermost barrier of the body and the first line of host defense, the skin presents a unique immunological interface to achieve these goals. The skin contains a high concentration of specialized immune cells, such as antigen-presenting cells and tissue-resident memory T cells. These cells feature diverse and potent combinations of immune receptors, providing access to cellular and molecular level control to modulate immune responses. Thus, skin provides accessible tissue, cellular, and molecular level controls that can be harnessed to improve immunotherapies. Biomaterial platforms - microneedles, nano- and micro-particles, scaffolds, and other technologies - are uniquely capable of modulating the specialized immunological niche in skin by targeting these distinct biological levels of control. This review highlights recent pre-clinical and clinical advances in biomaterial-based approaches to target and modulate immune signaling in the skin at the tissue, cellular, and molecular levels for immunotherapeutic applications. We begin by discussing skin cytoarchitecture and resident immune cells to establish the biological rationale for skin-targeting immunotherapies. This is followed by a critical presentation of biomaterial-based pre-clinical and clinical studies aimed at controlling the immune response in the skin for immunotherapy and therapeutic vaccine applications in cancer, allergy, and autoimmunity.

Laser microporation facilitates topical drug delivery: a comprehensive review about preclinical development and clinical application

INTRODUCTION

Topical drug delivery is highly attractive and yet faces tissue barrier challenges. Different physical and chemical methods have been explored to facilitate topical drug delivery.

AREAS COVERED

Ablative fractional laser (AFL) has been widely explored by the scientific community and dermatologists to facilitate topical drug delivery since its advent less than two decades ago. This review introduces the major efforts in exploration of AFL to facilitate transdermal, transungual, and transocular drug delivery in preclinical and clinical settings.

EXPERT OPINION

Most of the preclinical and clinical studies find AFL to be safe and highly effective to facilitate topical drug delivery with little restriction on physicochemical properties of drugs. Clinical studies support AFL to enhance drug efficacy, shorten treatment time, reduce pain, improve cosmetic outcomes, reduce systemic drug exposure, and improve safety. Considering most of the clinical trials so far involved a small sample size and were in early phase, future trials will benefit from enrolling a large group of patients for thorough evaluation of the safety and efficacy of AFL-assisted topical drug delivery. The manufacturing of small and less costly AFL devices will also facilitate the translation of AFL-assisted topical drug delivery.

Preparation of Levothyroxine Transdermal Gels and Preliminary Pharmacokinetic Study in Hypothyroidism Rat Model

Background:

Hypothyroidism is a common disorder due to inadequate thyroid hormone secretion. In patients with hypothyroidism, levothyroxine (LT4) is the treatment of choice, and tablets are the most common dosage form. However, the main limitation of tablet LT4 is malabsorption.

Objective:

This study intends to develop a new dosage form of percutaneous drug delivery for levothyroxine. Absorption of levothyroxine sodium through the application of gel formulation was studied using a hypothyroidism rat model.

Methods:

A formulation of levothyroxine sodium gel was developed and selected. In-vitro transdermal experiments were performed using the vertical Franz diffusion pool method, and gel formulation was used for animal research (hypothyroidism rats model). Total 30 rats were randomly divided into 6 groups, and one was the normal control group. The other 5 groups were prepared as hypothyroidism models. After applying different doses of gel preparation to the rat model, we measured serum total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) using fluorescence determination of luminescence immunoassay.

Results:

The optimum formulation of levothyroxine gels comprised 20% polyvinyl alcohol (PVA), 5% glycerol, 2% azone, and 6% oleic acid. The application of levothyroxine sodium gel resulted in quick and smooth action so that the predicted level of the normal control group could be reached within 2 weeks, and it lasted steadily for 8 weeks.

Conclusion:

This research study successfully developed and tested an optimal formulation of levothyroxine gel with therapeutic benefit on hypothyroidism in rats.

PCR-tips for rapid diagnosis of bacterial pathogens

Micropipette tips are currently among the most used disposable devices in bioresearch and development laboratories. Their main application is the fractionation of solutions. New functionalities have recently been added to this device, widening their applications. This paper analyzed disposable micropipette tips as reagent holders of PCR reagents. PCR has become a prevalent and often indispensable technique in biological laboratories for various applications, such as the detection of coronavirus and other infectious diseases. A functional micropipette tip was implemented to simplify PCR analysis and reduce the contamination chances of deoxynucleotides and specific primers. This disposable device is prepared by tip coating processes of reagents, using polyvinyl alcohol polymer and additives. The coated layer is optimized to load and release PCR reagents efficiently. As a proof of concept, we show that the detection of Bordetella pertussis, the etiological agent of whooping cough whose diagnostic relies on PCR, can be quickly done using practical-functional tips. This device is an excellent example of testing the functionality and contribution of molecular diagnostic PCR tips. KEY POINTS: • Functional micropipette tips are prepared by coating with dNTPs and primers. • Functional tips are used to replace dNTPs and primers in the PCR master mix. • PCR diagnostic of Bordetella pertussis is performed using functional tips.

Easy Fabrication of a Polymeric Transparent Sheet to Combat Microbial Infection

Surges in infectious diseases and their transmission in households and commercial and healthcare settings have increased the use of polymeric materials as protective covers. Despite ongoing efforts, conventional polymeric materials still pose the threat of surface-associated transmission of pathogens due to the fact that they lack antimicrobial properties. Here, we have developed an easy-to-fabricate polymeric sheet [quaternary polymeric transparent sheet (QPTS)] that shows an excellent antimicrobial property and is also transparent in nature, increasing its practical applications in a wide range of surfaces. The sheet was fabricated by combining cationic amphiphilic water-soluble polyethylenimine derivative (QPEINH-C₆) and poly(vinyl alcohol) (PVA). The optimum composition (QPTS-3) exhibited a complete reduction of bacterial and fungal infection (∼3-4 log reduction) within 15 min. QPTS-3 also exhibited activity against antibiotic-insusceptible metabolically inactive bacterial cells. The sheet prevented the growth of MRSA biofilm even after 72 h of incubation, which was confirmed through electron microscopy on the QPTS sheet. Most importantly, ∼99.9% of the influenza viral load was reduced completely within 30 min of exposure of the sheet. Apart from the antimicrobial property, the sheet successfully retained its transparency (∼88%) and maintained a significant mechanical strength (∼15 N), highlighting its potential applications in commercial and healthcare settings.

The Importance of Nanocarrier Design and Composition for an Efficient Nanoparticle-Mediated Transdermal Vaccination

The World Health Organization estimates that the pandemic caused by the SARS-CoV-2 virus claimed more than 3 million lives in 2020 alone. This situation has highlighted the importance of vaccination programs and the urgency of working on new technologies that allow an efficient, safe, and effective immunization. From this perspective, nanomedicine has provided novel tools for the design of the new generation of vaccines. Among the challenges of the new vaccine generations is the search for alternative routes of antigen delivery due to costs, risks, need for trained personnel, and low acceptance in the population associated with the parenteral route. Along these lines, transdermal immunization has been raised as a promising alternative for antigen delivery and vaccination based on a large absorption surface and an abundance of immune system cells. These features contribute to a high barrier capacity and high immunological efficiency for transdermal immunization. However, the stratum corneum barrier constitutes a significant challenge for generating new pharmaceutical forms for transdermal antigen delivery. This review addresses the biological bases for transdermal immunomodulation and the technological advances in the field of nanomedicine, from the passage of antigens facilitated by devices to cross the stratum corneum, to the design of nanosystems, with an emphasis on the importance of design and composition towards the new generation of needle-free nanometric transdermal systems.

Laser facilitated epicutaneous peptide immunization using dry patch technology

The skin has been intensely investigated as a target tissue for immunization because it is populated by multiple types of antigen presenting cells. Directly addressing dendritic cells or Langerhans cells in vivo represents an attractive strategy for inducing T cell responses in cancer immunotherapy. We and others have studied fractional laser ablation as a novel method combining efficient delivery of macromolecules to the skin with an inherent adjuvant effect of laser illumination. In this proof of concept study, we demonstrate the feasibility of peptide delivery to the skin using the P.L.E.A.S.E. professional Erb:YAG fractional infrared laser together with EPIMMUN patches. In an ovalbumin mouse model we demonstrate that a dry patch formulation of SIINFEKL peptide in combination with CpG-ODN1826, but not imiquimod or polyI:C, induces potent cytotoxic T cell responses, which can be further boosted by co-delivery of the pan-helper T cell epitope PADRE.

Fabrication and Characterization of Poly (vinyl alcohol) and Chitosan Oligosaccharide-Based Blend Films

In the present study, we report the development of poly (vinyl alcohol) (PVA) and chitosan oligosaccharide (COS)-based novel blend films. The concentration of COS was varied between 2.5-10.0 wt% within the films. The inclusion of COS added a brown hue to the films. FTIR spectroscopy revealed that the extent of intermolecular hydrogen bonding was most prominent in the film that contained 5.0 wt% of COS. The diffractograms showed that COS altered the degree of crystallinity of the films in a composition-dependent manner. As evident from the thermal analysis, COS content profoundly impacted the evaporation of water molecules from the composite films. Stress relaxation studies demonstrated that the blend films exhibited more mechanical stability as compared to the control film. The impedance profiles indicated the capacitive-dominant behavior of the prepared films. Ciprofloxacin HCl-loaded films showed excellent antimicrobial activity against Escherichia coli and Bacillus cereus. The prepared films were observed to be biocompatible. Hence, the prepared PVA/COS-based blend films may be explored for drug delivery applications.

Enhancing Permeation of Drug Molecules Across the Skin via Delivery in Nanocarriers: Novel Strategies for Effective Transdermal Applications

The transdermal route of administration provides numerous advantages over conventional routes i.e., oral or injectable for the treatment of different diseases and cosmetics applications. The skin also works as a reservoir, thus deliver the penetrated drug for more extended periods in a sustained manner. It reduces toxicity and local irritation due to multiple sites for absorption and owes the option of avoiding systemic side effects. However, the transdermal route of delivery for many drugs is limited since very few drugs can be delivered at a viable rate using this route. The stratum corneum of skin works as an effective barrier, limiting most drugs' penetration posing difficulty to cross through the skin. Fortunately, some non-invasive methods can significantly enhance the penetration of drugs through this barrier. The use of nanocarriers for increasing the range of available drugs for the transdermal delivery has emerged as a valuable and exciting alternative. Both the lipophilic and hydrophilic drugs can be delivered via a range of nanocarriers through the stratum corneum with the possibility of having local or systemic effects to treat various diseases. In this review, the skin structure and major obstacle for transdermal drug delivery, different nanocarriers used for transdermal delivery, i.e., nanoparticles, ethosomes, dendrimers, liposomes, etc., have been discussed. Some recent examples of the combination of nanocarrier and physical methods, including iontophoresis, ultrasound, laser, and microneedles, have also been discussed for improving the therapeutic efficacy of transdermal drugs. Limitations and future perspectives of nanocarriers for transdermal drug delivery have been summarized at the end of this manuscript.

Preparation and Thermal Decomposition Kinetics of a New Type of a Magnetic Targeting Drug Carrier

We have designed a new magnetic targeting drug carrier Fe3O4-PVA with a core of triiron tetroxide (Fe3O4) and a shell made of polyvinyl alcohol (PVA) to improve the hydrophilicity of Fe3O4. With adriamycin hydrochloride as a model drug, this study goes on to measure the drug carrier performance of Fe3O4-PVA. In addition, the thermal stability and enthalpy of thermal decomposition of Fe3O4-PVA were measured using a differential scanning calorimeter with a non-isothermal decomposition method. The kinetics of thermal decomposition of Fe3O4-PVA were also investigated. Over the course of this study, it was determined that the resulting drug carrier Fe3O4-PVA exhibited high drug loading levels and excellent release levels.

Comparison of the performance of magnetic targeting drug carriers prepared using two synthesis methods

In this paper, two methods were used to prepare the magnetic targeting drug carrier Fe₃O₄–PVA@SH, the step-by-step method and the one-pot method. The loading and release properties of the compound were measured. The results show that the Fe₃O₄–PVA@SH prepared using both methods exhibited excellent drug delivery properties in an environment that simulates human body fluid (pH 7.2) and a lysosomal in vitro simulation (pH 4.7). In applications such as drug delivery, magnetic targeted drug carriers prepared by both methods demonstrated superparamagnetism, high fat solubility, high hydroxyl content, and good water solubility.

Roadmap for the synthesis of Fe₃O₄–PVA@SH using the step-by-step method and one-pot method.

Preparation of amphiphilic magnetic polyvinyl alcohol targeted drug carrier and drug delivery research

Currently, magnetic applications have great potential for development in the field of drug carriers. In this paper, Fe₃O₄-PVA@SH, an amphiphilic magnetically targeting drug carrier, was prepared by using Fe₃O₄ and PVA with thiohydrazide-iminopropyltriethoxysilane(TIPTS). The loading capacity of Fe₃O₄-PVA@SH on Aspirin and the drug release kinetics of loaded drugs were studied. The obtained Fe₃O₄-PVA@SH exhibits excellent drug release properties in simulating the human body fluid environment (pH 7.2). Since magnetically targeting drug carriers are readily available and have excellent biocompatibility and the characteristics of drug release. This work’s development, preparing amphiphilic magnetically targeting drug carriers in drug delivery and other fields, has great significance.

Prospective Nanotechnology-Based Strategies for Enhanced Intra- and Transdermal Delivery of Antifungal Drugs

Topical therapy of superficial fungal infections allows the prevention of systemic side effects and provides drug targeting at the site of disease. However, an appropriate drug concentration in these sites should be provided to ensure the efficacy of such local treatment. The enhancement of intra- and transdermal penetration and accumulation of antifungal drugs is an important aspect here. The present overview is focused on novel nano-based formulations served to improve antimycotic penetration through the skin. Furthermore, it summarizes various approaches towards the stimulation of drug penetration through and into the stratum corneum and hair follicles, which are considered to be promising for the future improvement of superficial antifungal therapy as providing the drug localization and prolonged storage property at the targeted area.

Laser facilitates week-long sustained transdermal drug delivery at high doses

Traditional patches are most successful in transdermal delivery of low-dose hydrophobic drugs. Week-long transdermal delivery of high-dose hydrophilic drugs remains a big challenge. This study explored ablative fractional laser (AFL) to assist 3-day to week-long sustained transdermal delivery of powder hydrophilic drugs in murine models. Bulk drug powder was coated into reservoir patches followed by topical application onto AFL-treated skin. Water evaporated from AFL-generated skin microchannels (MCs) gradually dissolve topical drug powder to elicit multi-day sustained drug delivery. Using sulforhodamine b, zidovudine, and bovine serum albumin as model hydrophilic drugs, we found tapped coating could coat 10-20 mg drug per 0.5 cm² reservoir patch to elicit 3-day sustained delivery, while compression coating could coat ~35-70 mg drug per 0.5 cm² reservoir patch to elicit week-long sustained delivery. Besides sustained drug delivery, AFL-assisted powder reservoir patch delivery showed a good safety. AFL-generated skin MCs resealed in 1-2 days and completely recovered in 3 days after the week-long sustained delivery. AFL-assisted powder reservoir patch delivery involves no complex powder formulation and only requires incorporation of highly water-soluble mannitol or a similar excipient to elicit the high-efficient delivery. Enlarging reservoir patch size to 10 cm² can conveniently expand the delivery capacity to gram scale. To our knowledge, this is the first time that high-dose week-long sustained transdermal delivery of hydrophilic drugs was achieved via a simple laser-based powder delivery platform.

Fundamentals of fractional laser-assisted drug delivery: An in-depth guide to experimental methodology and data interpretation

In the decade since their advent, ablative fractional lasers have emerged as powerful tools to enhance drug delivery to and through the skin. Effective and highly customizable, laser-assisted drug delivery (LADD) has led to improved therapeutic outcomes for several medical indications. However, for LADD to reach maturity as a standard treatment technique, a greater appreciation of its underlying science is needed. This work aims to provide an in-depth guide to the technology's fundamental principles, experimental methodology and unique aspects of LADD data interpretation. We show that drug's physicochemical properties including solubility, molecular weight and tissue binding behavior, are crucial determinants of how laser channel morphology influences topical delivery. Furthermore, we identify strengths and limitations of experimental models and drug detection techniques, interrogating the usefulness of in vitro data in predicting LADD in vivo. By compiling insights from over 75 studies, we ultimately devise an approach for intelligent application of LADD, supporting its implementation in the clinical setting.

Controlled Release Film Forming Systems in Drug Delivery: The Potential for Efficient Drug Delivery

Despite many available approaches for transdermal drug delivery, patient compliance and drug targeting at the desired concentration are still concerns for effective therapies. Precise and efficient film-forming systems provide great potential for controlling drug delivery through the skin with the combined advantages of films and hydrogels. The associated disadvantages of both systems (films and hydrogels) will be overcome in film-forming systems. Different strategies have been designed to control drug release through the skin, including changes to film-forming polymers, plasticizers, additives or even model drugs in formulations. In the current review, we aim to discuss the recent advances in film-forming systems to provide the principles and review the methods of these systems as applied to controlled drug release. Advances in the design of film-forming systems open a new generation of these systems.

Transcutaneous delivery of DNA/mRNA for cancer therapeutic vaccination

Therapeutic vaccination is a promising strategy for the immunotherapy of cancers. It eradicates cancer cells by evoking and strengthening the patient's own immune system. Because of the easy access and sophisticated immune networks, the skin becomes an ideal target organ for vaccination. Genetic vaccines have been widely investigated, with the advantages of the delivery of multiple antigens and a lower cost for production compared to protein/peptide vaccines. This review summarizes the advances made with respect to the transcutaneous delivery of DNA/mRNA for cancer therapeutic vaccination and also gives a brief description of the immunological milieu of the skin and the importance of dendritic cell-targeting in vaccine delivery, as well as the technologies that aim to facilitate antigen delivery and modulate antigen-presenting cells, thus improving cellular responses. The applications of genetic vaccines encoding tumor antigens delivered through the skin route, both in preclinical and clinical trials, are outlined.

Epidermal micro-perforation potentiates the efficacy of epicutaneous vaccination

The skin is an immune organ comprised of a large network of antigen-presenting cells such as dendritic cells, making it an attractive target for the development of new vaccines and immunotherapies. Recently, we developed a new innovative and non-invasive vaccination method without adjuvant based on epicutaneous vaccine patches on which antigen forms a dry deposit. Here we describe in mice a method for potentiating the efficacy of our epicutaneous vaccination approach using a minimally invasive and epidermis-limited skin preparation based on laser-induced micro-perforation. Our results showed that epidermal micro-perforation increased trans-epidermal water loss, resulting in an enhancement of antigen solubilization from the surface of the patch, and increased the quantity of antigen delivered to the epidermis. Importantly, this was not associated with an increase in systemic passage of the antigen. Skin micro-perforation slightly activated keratinocytes without inducing an excessive level of local inflammation. Moreover, epidermal micro-perforation improved antigen capture by epidermal dendritic cells and specifically increased the level of Langerhans cells activation. Finally, we observed that epidermal micro-perforation significantly increased the level of the specific antibody response induced by our epicutaneous Pertussis vaccine candidate containing non-adsorbed recombinant Pertussis Toxin and reduced the amount of antigen dose required. Overall, these data confirm the benefit of a minimal and controlled epidermal preparation for improving the effectiveness of an epicutaneous patch-based vaccine, without adversely affecting the safety of the method.